Acoustic ash removal

ABSTRACT

An acoustic system having a plurality of speakers applying acoustic energy as a series of acoustic waves to various target sites on the exterior of the reactor to vibrate and deflect the interior surfaces of the reactor structure such that the slag is dislodged from the internal surfaces of the reactor structure. Each speaker generates acoustic waves having a waveform corresponding to the resonant frequency of the ash crystallized on the reactor structures. The acoustic waves induce vibrations and/or deflections in the portion of the reactor wall to which the slag is engaged as well as the slag itself breaking the interstitial bonds of the slag deposit and bonding holding the slag to the wall. The separated or disintegrated slag can then be gravimetrically fall to the bottom of the reactor for removal from the reactor.

RELATED FOREIGN APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication No. 61/569,476 entitled SONIQ CLEANING APPROACH ANDSUGGESTED DEVELOPMENT AREAS filed Dec. 12, 2011, which is incorporatedherein in its entirety.

FIELD OF THE INVENTION

The present invention is directed to an ultrasonic cleaning system andrelated method of using for removing slag and other industrial buildupfrom the interior surfaces of reactors.

BACKGROUND OF THE INVENTION

In coal power plants, coal is combusted in large reactors to vaporize awater stream that is then used to operate a steam turbine and generateelectricity. The combustion of the coal generates large quantities ofash particulates. “Bottom ash” or “coal ash” typically comprises largerash particulates or molten ash that gravimetrically falls to the bottomof the reactor. The bottom ash is removed by accessing the bottom of thereactor and removing the ash collected at the bottom of the reactor aseither dry or molten ash. As depicted in FIG. 1, “Fly ash” typicallycomprises smaller dry particulates ranging in size from 0.5 μm to 100 μmthat are carried on the vapor currents within the reactor and beforebeing captured by filters at the reactor chimney. A portion of the flyash can crystallize on the walls and other internal surfaces of thereactor forming slag deposits that must be removed periodically for thereactor to operate efficiently.

Fly ash typically comprises substantial amounts of amorphous andcrystalline silicon dioxide (SiO₂), calcium oxide (CaO), aluminum oxide(Al₂O₃) and iron oxide (Fe₂O₃). The oxide components produce a hard,crystalline material that adheres to the internal surfaces of thereactor and can be difficult to separate from the reactor wall orinternal structures without substantial mechanical effort. Depending onthe amount of silicon oxide present, the slag can comprise a rounded,smooth texture or a sharp, pointed texture which can injure workersremoving the slag. The slag can also include a plurality of toxicconstituents including one or more of the following elements orsubstances in quantities from trace amounts to several weight percent:arsenic, beryllium, boron, cadmium, chromium, chromium VI, cobalt, lead,manganese, mercury, molybdenum, selenium, strontium, thallium, andvanadium, along with dioxins and PAH compounds. Accordingly, in order tominimize worker exposure to the toxic materials, only certain techniquesthat can be used to separate the slag from the reactor structure.

A conventional approach to cleaning reactors is to have workers enterthe reactor and manually remove the slag with hand tools. The inherentchallenge is that the reactors can be very large and are often severalstories in height making manual removal of the slag tedious and timeconsuming. Projectile weapons, such as shotguns firing soft lead shot,are fired at the slag from inside the reactor chamber dislodge the slagfrom the surfaces of the reactor structure. Aside from the inherentdanger of firing a projectile weapon within an enclosed space, thetypically large amount of slag that must be removed requires asubstantial number of shots to remove the slag creating a large quantityof shot that must also be removed. Similarly, liquid cleaners can beapplied to dissolve or loosen the slag from the reactor surfaces. Thedissolved slag or the liquid cleaner itself can be highly toxic to theusers particularly if a portion of the slag or liquid cleaner vaporizeswithin the reactor. All of the approaches require shutdown of thereactor and require workers to enter the potentially toxic environmentwithin the reactor to manually remove the slag.

The inherent drawback of manual cleaning techniques and as well as riskof toxic exposure to workers cleaning the reactor demonstrates a needfor an improved cleaning technique that can separate the slag from thereactor structure efficiently and cleanly.

SUMMARY OF THE INVENTION

The present invention is generally directed to an acoustic system havinga plurality of speakers applying acoustic energy as a series of acousticwaves to various target sites on the exterior of the reactor to vibrateand deflect surfaces of the reactor structure such that the slag isdislodged from the internal surfaces of the reactor structure. Eachspeaker comprises a driver for generating acoustic waves having awaveform corresponding to the resonant frequency of the ash crystallizedon the reactor structures. The acoustic waves induce vibrations and/ordeflections in the portion of the reactor wall to which the slag isengaged as well as the slag itself breaking the interstitial bonds ofthe slag deposit and bonding holding the slag to the wall. In oneaspect, the internal structure of the reactor proximate to the portionof the wall impacted by the acoustic waves can operate as a waveguidetransmitting the acoustic energy from the acoustic waves deeper into theinternal surfaces of the reactor structure. The separated ordisintegrated slag can then gravimetrically fall to the bottom of thereactor for removal from the reactor.

In general, the variables relevant to the removal of slag are: slaglocation in the boiler; number and spacing of speakers; volume ofapplication (amplitude=sound pressure): duration of sound applicationduring an acoustic pass; acoustic frequency of interest; acoustic waveshape; frequency of acoustic application; wave combinations andpermutations; and sweep amplitude and duration.

In one aspect, the speakers can be oriented to direct the acoustic wavesat portions of the reactor wall unsupported by the reactor supportstructure or mounting elements. The unsupported portion of the reactorwall allows for inducement of the maximum possible deflection andoscillation from the acoustic waves. In one aspect, the centroid of theacoustic waves can be targeted at a point on the reactor exteriorequidistant between the underlying reactor support structures along alinear axis, wherein the linear axis is a horizontal axis or a verticalaxis. In one aspect, the spherical acoustic waves are oriented such thatthe centroid of each wave is normal to the reactor surface.

In one aspect, the operation of the speakers can be cycled betweenactive cycles in which the acoustic energy is applied to the reactor andrest cycles in which little or no acoustic energy is applied to thereactor. The amplitude and/or frequency of the acoustic waves appliedduring each active cycle can be modulated to correspond to changingresonant frequency of the slag as portions of the amount of slagattached to the reactor structure lessons. Alternatively, the acousticwaves can be modulated according to the chemical makeup of the slag tobe removed. In one aspect, the exterior surface of the reactor structurecan be struck during the rest cycle proximate to the slag deposits toinduce an acoustic response for measuring the resonant frequency of theslag still adhered to the reactor structure. In certain aspects, theamplitudes of the acoustic waves must range across a substantial rangeto provide the necessary resonant frequencies.

In one aspect, the acoustic waves can be initially introduced at a lowfrequency before the acoustic waves before the amplitude and/or thefrequency the acoustic waves are varied through a predeterminedspectrum. The varied waveforms can correspond to the resonantfrequencies of a range of particulate sizes and compositions therebydisrupting the bonding of a plurality of particles. With mountedacoustic systems the programmed sweep of waveforms can be tailored forparticular operating conditions and chemical compositions of the slag.

A method of removing slag from an internal surface of a reactor,according to an embodiment of the present invention, comprisesidentifying a target point on an exterior surface of the reactor,wherein the target point is equidistant from at least two supportstructures along at least one linear axis. The method further comprisespositioning a speaker a predetermined distance from the reactor, whereinthe speaker comprises a driver for generating acoustic waves and a conefor directing the acoustic waves toward the target point. The methodalso comprises actuating the driver to generate acoustic waves thatimpact the target point of the reactor inducing oscillation anddeflection of the exterior surface of the reactor. In one aspect, thespeakers are oriented such that the acoustic waves have a centroidnormal to the exterior surface of the reactor. The method furthercomprises examining the displacement of the reactor wall in response tothe acoustic waves. In one aspect, the method can also comprise alteringat least one waveform factor of the acoustic waves, wherein the waveformfactor can be selected from the amplitude of the acoustic waves, thefrequency of the acoustic waves and combinations thereof. In thisconfiguration, the method can further comprise applying second acousticwaves from the speaker to the target point.

A method of removing slag from an internal surface of a reactor,according to an embodiment of the present invention, comprises locatingan exterior surface corresponding to the interior surface to which theslag is adhered. The method also comprises striking the located exteriorsurface to induce an acoustic response from the slag adhered to theinterior surface. The method further comprises evaluating the acousticresponse to determine a resonant frequency corresponding to the slagadhered to the interior surface. The method further comprises selectinga wave frequency and an amplitude for generating acoustic wavescorresponding to the identified resonant frequency. The method alsocomprises positioning at least one speaker proximate to the locatedexterior surface. The method further comprises operating the speakers toapply acoustic waves having the selected waves frequency and amplitudeto induce a response in the reactor at the resonant frequency, whereinthe response at the resonant frequency disintegrates or separates theslag from the interior surface.

In one aspect, the method can further comprise striking the reactor asecond time to generate a second acoustic response. In thisconfiguration, the second acoustic response can be evaluated toascertain whether the wave frequency and amplitude must be altered toproduce at least one second acoustic wave corresponding to the newresonant frequency. The process can be repeated as a portion of the slaggradually shed from the interior surface of the reactor.

An acoustic system for generating acoustic waves for removing slag froma reactor, according to an embodiment of the present invention, cancomprise a driver assembly and a cone assembly. Each cone comprises afirst end and a second end, wherein the cone comprises a generallyfrustoconical shape in which the first end has a smaller diameter thanthe second end and is positioned against the driver assembly. The conedefines a central axis intersecting the center of the first and secondends. The driver assembly comprises a speaker coil and a permanentmagnet, wherein the speaker coil is operably affixed to the first end ofthe cone. In operation, an alternating current is passed through thespeaker coil to oscillate the speaker coil and cone along the centralaxis to generate acoustic waves centered on the central axis, whereinthe central axis can be aligned with a target point on the exterior ofthe reactor.

In one aspect, the speakers can be positioned such that the second endof the cone is a predetermined distance from the reactor exterior. Thedistance creates a heat dissipation zone reducing the heat transferredfrom the reactor to the speakers. It was found that the heat transferfrom the reactor to the speakers can reduce the longevity of thespeaker. The distance allows the speakers to be mounted in situ toprovide regular acoustic treatments to the reactor to maintain efficientoperation of the reactor without substantial down time for repositioningand targeting of the reactor. The mounted speakers can be permanentlyoriented at problem spots of the reactor where slag build up is likelyor particularly heavy. In one aspect, the acoustic energy can be appliedto the reactor during normal operation of the reactor to prevent the flyash particulates from settling on the interior surface of the reactor.In this configuration, the constant acoustic energy limits the buildupof slag deposits and prevents large slag deposits from forming on theinterior surfaces.

A speaker, according to an embodiment of the present invention,comprises a driver assembly and a cone assembly. The driver assembly cancomprise a speaker coil and a permanent magnet contained within a driverhousing, wherein supplying an alternating current to the speaker coilcauses the coil to oscillate along a central linear axis. The coneassembly comprises a cone flexibly mounted to a speaker housing, whereinthe cone oscillates relative to the speaker housing along the centrallinear axis as the speaker coil is oscillated. The cone comprises afirst end and a second end, wherein the cone comprises a frustoconicalshape in which the first end has a smaller diameter than the second end.

In one aspect, the driver housing can define at least one hole in therear face of the driver housing. The oscillation of the speaker coiloscillates air into and out of the holes in the driver housing.Additional air is drawn perpendicular to a plane defined by the holes tocreate a synthetic jet oriented perpendicular to the plane of the holethat expels air rearward from the driver housing cooling the driver. Theair flow cools the driver assembly increasing the longevity of thedriver assembly.

In one aspect, the driver assembly can further comprise a safety circuitlinked to the speaker coil to monitor the draw of the speaker coil. Itwas found that the temperature in the driver assembly increases due tofriction from the oscillation of the speaker coil and cone, which inturn increases the resistance of the speaker coil requiring additionalpower drawn to continue operation of the speaker. The ongoing cycle ofadditional power draw and increased resistance can result in thermalrunway resulting in permanent damage to the speaker. The safety circuitcomprises a plurality of rectifiers arranged in parallel and set atgraduated power draw threshold levels, wherein each of the rectifierscloses as the power draw of the speaker coil exceeds the threshold levelcorresponding to the rectifier until the power coil is completely shutoff. As the speaker cools and the power draw drops, the rectifiersreopen to allow the speaker to safely resume operation.

A method of removing slag from an internal surface of a reactor,according to an embodiment of the present invention, comprises locatingan exterior surface corresponding to the interior surface to which theslag/ash buildup occurs. The method also comprises analyzing theposition of the buildup relative to the structure for placement ofspeakers. The speakers are positioned so that the sound/acoustic wavesfrom the speakers impinges normal to the structure. The amp output isadjusted to eliminate clipping. The system resonance of the structure isthen determined. The acoustic waveform is selected based on striking thelocated exterior surface to induce an acoustic response from the slagadhered to the interior surface. The method further comprises evaluatingthe acoustic response to determine a resonant frequency corresponding tothe slag adhered to the interior surface. The method further comprisesselecting a wave frequency and an amplitude for generating acousticwaves corresponding to the identified resonant frequency. Next theoperator sets the sweep at +/−25 hz. The method also comprisespositioning at least one speaker proximate to the located exteriorsurface. The method further comprises operating the speakers to applyacoustic waves having the selected waves frequency and amplitude toinduce a response in the reactor at the resonant frequency, wherein theresponse at the resonant frequency disintegrates or separates the slagfrom the interior surface. The system may be cycled on/off to induce ashremoval. The speakers may be repositioned and the entire processrepeated. The duration of the removal process can be approximately onehour per speaker location.

The above summary of the various representative embodiments of theinvention is not intended to describe each illustrated embodiment orevery implementation of the invention. Rather, the embodiments arechosen and described so that others skilled in the art can appreciateand understand the principles and practices of the invention. Thefigures in the detailed description that follow more particularlyexemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is a photograph of scanning electron microscope image of fly ashmagnified 2000 times.

FIG. 2 is a cross-sectional side view of a speaker according to anembodiment of the present invention.

FIG. 3 is a representative side cross-sectional side view demonstratingformation of a synthetic jet from a rear face of a driver assemblyaccording to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a safety circuit according to anembodiment of the present invention.

FIG. 5 is a representative perspective view illustrating an arrangementof speakers according to an embodiment of the present invention.

FIG. 6 is a representative plan view illustrating an arrangement ofspeakers according to an embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a method of slag removalaccording to an embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating a method of slag removalaccording to an embodiment of the present invention.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

As depicted in FIG. 2, an acoustic system 20, according to an embodimentof the present invention, comprises at least one speaker 22 having adriver assembly 24 and a cone assembly 25. The driver assembly 24further comprises a speaker coil 26, a driver 28, a permanent magnet 30and a driver housing 32. As depicted in FIG. 2, the speaker coil 26 isarranged in a cylindrical coil around the driver 28, wherein thepermanent magnet 30 comprises a cylindrical pipe shape encircling thecylindrical speaker coil 26. Alternatively, the permanent magnet 28 cancomprise a cylindrical shape extending into the center of the speakercoil 26, wherein the driver 28 defines an inner cavity extendinglongitudinally through the speaker coil 26. The driver housing 32comprises a cup shape having an open front end 34 and a closed rear end36. The cone assembly 26 can comprise a cone 38 and a speaker housing40. The cone 38 comprises a frustoconical shape having a first end 42and a second end 44, wherein the first end 42 has a diameter less thanthe second end 44. The speaker housing 40 defines a speaker opening 46.The first end 42 is affixed to the driver 28 while the second end 44 ofthe cone 38 is flexibly affixed to the speaker housing 40 with a hinge48 at the speaker opening 46.

In operation, an alternating current can be supplied to the speaker coil26 causing the speaker coil 26 and the attached driver 28 to oscillatealong a central axis a-a extending through the center of the first andsecond ends 42, 44 of the cone 38. In one aspect, the driver housing 32can comprise a divider 50 having an orifice 52 for receiving the driver28, wherein the orifice 52 comprises a bearing 54 for guiding the driver28 along the central axis a-a. The oscillation of the driver 28correspondingly oscillates the cone 38 along the central axis a-a togenerate a series of acoustic waves centered on the central axis a-a.The speaker 22 can be oriented to direct the acoustic waves at atargeted site by aligning the central axis a-a with the target site.

In one aspect, the speaker 22 can further comprise a resonance chamberpositioned at the second end 44 of the cone 38. The resonance chamberfocuses the acoustic energy generated by the oscillating cone 38 anddirects the acoustic energy along the central axis a-a. In one aspect,the resonance chamber can be shaped to act as a wave guide focusing theacoustic waves generated by the cone 38 delaying the expansion of theacoustic waves.

As depicted in FIG. 3, the driver housing 32 can define at least onehole 56 in the closed rear end 36 of the driver housing 32. Thetemperature in the driver region increases due to friction. When thetemperature increases sufficiently, the resistance increases and athermal runaway results. To combat this temperature issue, holes aredrilled into the rear face of the structure housing the driver. In oneaspect, the hole 56 can be between 0.120 to 0.125 inches in diameter. Inthis configuration, the oscillation of the driver 28 through the orifice52 of the divider 50 causes oscillation of air through the hole 56creating a synthetic jet of air away from the rear of the driver housing32 to facilitate cooling of the driver assembly 24. The speaker acts asa diaphragm during operation. Expelled air forms toroids 33 due tovortex shedding at the orifice. Replenishment air 35 comes from thesurface which demonstrates an air exchange.

As depicted in FIG. 4, the induction coil 26 can be operably linked to asafety circuit for cutting off power to the induction coil 26 if thespeaker 22 overheats. Increased friction from the moving driver 28 andincreased temperature will in turn increase the amount of power drawn ofthe induction coil 26 to operate driver assembly 24. The safety circuitcomprises a plurality of rectifiers 27 arranged in parallel and set atgraduated power level thresholds. Each of the rectifiers 27 is adaptedto disconnect as the power level exceeds the corresponding power levelthreshold until all of the rectifiers 27 are disconnected and the powerto the induction coil 26 is cutoff and the speaker 22 is disabled. Asthe disabled speaker cools and the power draw lessens, the rectifiers 27reconnect in sequence to resume safe operation of the speaker 22.

As depicted in FIGS. 5-6, in one embodiment of the present invention,the acoustic system 20 can comprise a plurality of speakers 22 arrangedaround the exterior of a reactor 29. The reactor 29 generally comprisesa plurality of reactor supports overlaid with a reactor wall 31 havingan exterior surface and an interior surface. During combustion, the slagcan form on the interior surfaces and crystallize adhering to theinterior surface. Each speaker 22 can be oriented such that central axisa-a of each speaker 22 is oriented at point on the exterior surface ofthe reactor 29 proximate to a slag deposit on the interior surface. Thespeaker 22 can then be operated to transmit acoustic waves to theexterior surface of the reactor 29 to deflect and vibrate the reactorwall 31 to shake the slag deposit loose from the interior surface ordisintegrate the slag deposit. In one aspect, the cone 38 can be shapedto form a spherical wave, wherein the speaker 22 is oriented such thatthe centroid of each acoustic wave normal to the exterior of the reactorwall 31.

As depicted in FIG. 7, a method of removing a slag deposit from aninterior surface of the reactor wall, according to an embodiment of thepresent invention, comprises an evaluation step 210, a speakerpositioning step 220, an acoustic energy step 230 and an examinationstep 240. In one aspect, the method can further comprise an adjustmentstep 250.

In the evaluation step 210, the reactor is evaluated to identify atleast one target site on the exterior wall of the reactor wall. Thetarget site corresponds to a portion of the exterior surface of thereactor wall proximate to an interior surface of the reactor wall towhich the slag is adhered. In one aspect, the target site is selected tobe equidistant from at least two adjacent support structures along alinear axis. Alternatively, the target site can be relatively free offixtures and other reactor structures. In this configuration, the targetsite is at or proximate to the least supported point of that portion ofthe reactor wall. The linear axis can be a horizontal axis, a verticalaxis or a transverse axis depending on the underlying support structure.

In the placement step 220, each speaker 20 is oriented such that thecentral axis a-a of each speaker 20 aligns with the target site. In oneaspect, the speaker 20 is aligned with target site such that thecentroid of the acoustic waves is normal to the exterior surface of thereactor wall. As depicted in FIGS. 5-6, a plurality of speakers 20 canbe arranged in a ring around the reactor to provide acoustic energycontinuously around the periphery of the reactor.

In the acoustic energy step 230, the driver assembly 24 of each speaker22 is operated to apply a series of acoustic waves to the exteriorsurface of the reactor centered at the target site. In one aspect, theacoustic energy can be cycled between active cycles in which a pluralityof acoustic waves is directed at the reactor and rest cycles in whichthe speaker 20 is disabled. In one aspect, the active cycles andalternated with rest cycles, wherein each active cycle is about doublethe duration of the intervening rest cycles. In another aspect, eachactive cycle can comprise about 2 minutes and each intervening restcycle can comprise about 1 minute. In certain aspects, the acousticenergy step 230 can last between 1 to 2 hours.

In the examination step 240, the reactor is examined to determine theamount of slag removed from the interior surface of the reactor. Thereactor can also be examined to evaluate the amount of deflection andvibration of the reactor wall induced by the acoustic energy supplied bythe acoustic system 20.

In the adjustment step 250, the additional acoustic energy can besupplied to the reactor to dislodge additional slag. The duration of theactive cycles and the overall length of the acoustic energy step 230 canbe varied to further remove addition slag from the reactor.

It is envisioned that a white noise base at 10% of total amplitude maybe incorporated to help control the heat of the speaker.

As depicted in FIG. 8, a method of removing a slag deposit from aninterior surface of the reactor wall, according to an embodiment of thepresent invention, comprises an evaluation step 310, a positioning step320, a resonant frequency step 330, a selection step 340 and an acousticenergy step 350. In one aspect, the method further comprises a loop backcycle in which the resonant frequency step 330, the selection step 340and the acoustic energy steps 350 are repeated at least once.

In the evaluation step 310, the reactor is evaluated to identify atleast one target site on the exterior surface of the reactor wallcorresponding to a slag deposit on the interior surface of the reactorwall. In the position step 320, the speakers 22 can be positioned toalign the central axis a-a of each speaker aligned with one of theidentified target sites.

In the resonant frequency step 330, the exterior surface of the reactorwall is struck to induce an acoustic response corresponding to the sizeand chemical makeup of the slag deposits adhered to the inner surface ofthe reactor wall. The acoustic response is evaluated to determine aresonant frequency corresponding to the slag deposit and the presentcondition of the slag deposits within the reactor.

In the selection step 340, a desired frequency and a desired amplitudeis selected from a library of operating conditions at which the speaker22 to form an acoustic wave capable of inducing resonance in the reactorat the determined resonant frequency. The frequency, amplitude, durationof the active and rest cycles, and the overall treatment duration can beselected to provide the desired acoustic waveform characteristics.

In the acoustic energy step 350, the speaker 22 can be operated toprovide the acoustic energy to the reactor, wherein the speaker 22provides a plurality of acoustic waves having the selectedcharacteristics to induce resonance in the reactor to cause separationof the slag from the interior surfaces of the reactor. In one aspect,the resonant frequency step 330, the selection step 340 and the acousticenergy steps 350 are repeated as the slag is separated from the interiorsurface of the reactor. In this operation, the loop back cycle allowsfor adjustment of the acoustic waves to accommodate the changingresonant frequency of the slag deposits as portions of the slag areseparated from the interior surfaces of the reactor.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and described in detail. It is understood, however, that theintention is not to limit the invention to the particular embodimentsdescribed. On the contrary, the intention is to cover all modifications,equivalents, and alternatives falling within the spirit and scope of theinvention as defined by the appended claims.

1. An acoustic system for removing slag from an interior surface of areactor, comprising: at least one speaker further comprising: a driverassembly having a speaker coil and a permanent magnet, wherein thespeaker coil is positioned proximate to the permanent magnet such thatsupplying an alternating current to the speaker coil induces a magneticfield in the speaker coil oscillating the speaker coil along a centralaxis, and a cone assembly having a cone having a first end and a secondend, wherein the cone comprises a frustoconical shape in which the firstend has a smaller diameter than the second end, wherein the first end ofthe cone assembly is operably engaged to the speaker coil such that thecentral axis intersects the center of the first and second ends and theoscillation of the speaker coil induces a corresponding oscillation inthe cone along the central axis to generate at least one acoustic wavecentered on the central axis; wherein the speaker can be oriented tosupply at least one acoustic wave to the interior surface of the reactorto induce a deflection and vibration in the inner surface by aligningthe central axis with an exterior surface of the reactor correspondingto the interior surface.
 2. The acoustic system of claim 1, wherein thedriver assembly further comprises a driver housing for receiving thespeaker coil and permanent magnet, wherein the driver housing comprisesan open end through which the speaker coil is engaged to the cone and aclosed end defining at least one hole such that oscillation of thespeaker coil induces an oscillation of air through the holes.
 3. Theacoustic system of claim 1, wherein the speaker coil further comprises asafety circuit having a plurality of rectifiers arranged in parallel andset at graduated power thresholds, wherein the alternating currentpasses through the rectifiers causing each rectifier to disconnect asalternating current exceeds the corresponding power threshold until thespeaker coil is disconnected and ceases oscillating.
 4. A method forremoving slag from an interior surface of a reactor having a pluralityof structural supports, comprising: locating a target site on anexterior surface of the reactor corresponding to the interior surface,wherein the target site is approximately equidistant from at least twoadjacent structural supports along a linear axis; aligning a speakeradapted to provide at least one acoustic wave centered on a central axiswith the target site such that the central axis aligns with the targetsite; apply at least one first acoustic wave generated by the speaker tothe target site; resting for a predetermined time before applying atleast one second acoustic wave generated by the speaker to the targetsite; and examining the target site to ascertain the amount of slagremoved.
 5. The method of claim 4, further comprising applying at leastone third acoustic wave to the target site having at least one modifiedwaveform characteristic determined from the evaluation of the reactorfollowing the application of the at least one second wave, wherein thewaveform characteristic can be selected from the amplitude of theacoustic wave, the frequency of the acoustic wave, and combinationsthereof.
 6. A method for removing slag from an interior surface of areactor having a plurality of structural supports, comprising: locatinga target site on an exterior surface of the reactor corresponding to theinterior surface, wherein the target site is equidistant from at leasttwo adjacent structural supports along a linear axis; striking theexterior surface of the reactor at the target site to induce an acousticresponse from the reactor and the slag adhered to the interior surfaceof the reactor; evaluating the acoustic response to ascertain a resonantfrequency of the slag adhered to the interior surface of the reactor;selecting a first amplitude and a first frequency for an acoustic wavecapable of inducing resonance in the reactor and adhered slag at theresonant frequency; aligning a speaker adapted to provide the acousticwave centered on a central axis with the target site such that thecentral axis aligns with the target site; and applying at least onefirst acoustic wave having the selected first amplitude and firstfrequency to the target site to induce resonance in the reactor and theslag adhered to the interior surface.
 7. The method of claim 6, furthercomprising: striking the exterior surface of the reactor at the targetsite after application of the at least one first acoustic wave to inducean second acoustic response from the reactor and the slag still adheredto the interior surface of the reactor; evaluating the second acousticresponse to ascertain a second resonant frequency of the slag adhered tothe interior surface of the reactor; selecting a second amplitude and asecond frequency for a second acoustic wave capable of inducingresonance in the reactor and adhered slag at the second resonantfrequency; and applying at least one second acoustic wave having theselected second amplitude and second frequency to the target site toinduce resonance in the reactor and the slag adhered to the interiorsurface.